Two British tourists kidnapped in Congo's Virunga National Park have been released, according the UK Foreign Office.
A park ranger killed by the kidnappers has been named as Rachel Masika Baraka.
The men were gorilla trekking at Virunga National Park on the eastern border when their convoy was ambushed by armed militants.
"I pay tribute to the help of the DRC authorities and Congolese Insitute of Nature Conservation", he added.
"With Virunga National Park being within our zone of action, we have joined the park rangers for search operations for the people taken hostages", Major Guillaume Kaiko Ndjike, the army's spokesman in North Kivu, said on Saturday.
The Foreign and Commonwealth Office advises against all but essential travel to DRC capital Goma and has urged Britons not to go beyond the city.
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Police were led to the property by a phone call before dawn, Dawson said. "Based on what we do know, this is clearly a tragedy". Police confirmed the father of the children, Aaron Cockman, was also shocked and was being provided with support.
Virunga Park director, Emmanuel de Merode, said: "We are deeply saddened by the death of Virunga National Park Ranger Baraka, whose life was tragically cut short while protecting the passengers and driver".
Located in Congo's North Kivu province, the park is one of the most important conservation sites in the world, covering 7,800 square kilometres (3,011 miles) - three times the size of Luxembourg.
The park has experienced an increase in violence in recent months with armed groups staging a series of raids to steal resources, particularly charcoal.
It is home to to around a quarter of the world's critically endangered mountain gorillas and other endangered species as well as lions, elephants, hippos and a host of rare bird species. Mai-Mai militia were blamed for an attack last month in which six guards were killed.
A female wildlife ranger accompanying the pair was killed.
The advice says tourists are vulnerable if travelling without escorted transport in the eastern part of the country, and the "risk of kidnap or injury as a result of armed or criminal activity remains high".